1. Field of the Invention
The present invention relates to a robot system that detects an abnormal operation of an industrial robot.
2. Description of the Related Art
A device is conventionally known that detects acceleration and velocity of a tip portion of a robot arm and, if any of the acceleration and velocity is greater than a predetermined value, it is determined that the robot is in an abnormal state and brings the robot to an emergency stop. This device is described in Japanese Unexamined Patent Publication (kokai) No. H06-91587 (JP6-91587A).
However, when a sensor for detecting the acceleration and velocity fails, the device described in JP6-91587A cannot prevent the abnormal operation of the robot.